Margarine and vegetable oils are two of the absolute worst fats to eat. Both contain heart-harming trans fats, for example. Your best alternative for cooking is coconut oil, as it’s less susceptible to heat damage

Microwave popcorn, table salt, non-organic produce like potatoes, and unfermented soy products, including soy protein isolate, are more harmful than beneficial as they all contain hazardous contaminants

Most canned foods contain BPA, a toxic chemical. Acidity causes BPA to leach into your food. Stick to fresh fruits and vegetables, or switch over to brands that use glass containers instead—especially for acidic foods like tomatoes

By Dr. Mercola

Many foods have been heavily promoted as being healthy when they are nothing more than pernicious junk foods. In the featured article, Clean Plates1 founder Jared Koch shared his list of nine staple foods that are far less "good for you" than you've been led to believe.

Here, I expand on the selections that are mentioned in the featured article.

1. Canned Tomatoes

Many leading brands of canned foods contain BPA -- a toxic chemical linked to reproductive abnormalities, neurological effects, heightened risk of breast and prostate cancers, diabetes, heart disease and other serious health problems. According to Consumer Reports' testing, just a couple of servings of canned food can exceed the safety limits for daily BPA exposure for children.

High acidity — a prominent characteristic of tomatoes – causes BPA to leach into your food. To avoid this hazardous chemical, avoid canned foods entirely and stick to fresh fruits and vegetables, or switch over to brands that use glass containers instead—especially for acidic foods like tomatoes.

2. Processed Meats

As Koch warns, processed deli meats like salami, ham, and roast beef are typically made with meats from animals raised in confined animal feeding operations (CAFOs).

This means they're given growth hormones, antibiotics and other veterinary drugs, and raised in deplorable conditions that promote disease, these meats are also filled with sodium nitrite (a commonly used preservative and antimicrobial agent that also adds color and flavor) and other chemical flavorings and dyes.

Nitrites can be converted into nitrosamines in your body, which are potent cancer-causing chemicals. Research has linked nitrites to higher rates of colorectal, stomach and pancreatic cancer. But that's not all. Most processed deli meats also contain other cancer-promoting chemicals that are created during cooking. These include:

Heterocyclic Amines (HCAs) which are hazardous compounds created in meats and other foods that have been cooked at high temperatures. According to research, processed meats are clearly associated with an increased risk of stomach, colon and breast cancers.

Polycyclic Aromatic Hydrocarbons (PAHs): Many processed meats are smoked as part of the curing process, which causes PAHs to form. PAHs can also form when grilling. When fat drips onto the heat source, causing excess smoke, and the smoke surrounds your food, it can transfer cancer-causing PAHs to the meat.

Advanced Glycation End Products (AGEs): When food is cooked at high temperatures—including when it is pasteurized or sterilized—it increases the formation of AGEs in your food. AGEs build up in your body over time leading to oxidative stress, inflammation and an increased risk of heart disease, diabetes and kidney disease.

The truth is, processed meats are not a healthful choice for anyone and should be avoided entirely, according to a 2011 review of more than 7,000 clinical studies examining the connection between diet and cancer. The report was commissioned by The World Cancer Research Fund2 (WCRF) using money raised from the general public. Therefore the findings were not influenced by any vested interests, which makes it all the more reliable.

3. Margarine

The unfortunate result of the low-fat diet craze has been the shunning of healthful fats such as butter, and public health has declined as a result of this folly. There are a myriad of unhealthy components to margarine and other butter impostors, including:

Trans fats: These unnatural fats in margarine, shortenings and spreads are formed during the process of hydrogenation, which turns liquid vegetable oils into a solid fat. Trans fats contribute to heart disease, cancer, bone problems, hormonal imbalance and skin disease; infertility, difficulties in pregnancy and problems with lactation; and low birth weight, growth problems and learning disabilities in children. A US government panel of scientists determined that man-made trans fats are unsafe at any level.

Free radicals: Free radicals and other toxic breakdown products are the result of high temperature industrial processing of vegetable oils. They contribute to numerous health problems, including cancer and heart disease.

Emulsifiers and preservatives: Numerous additives of questionable safety are added to margarines and spreads. Most vegetable shortening is stabilized with preservatives like BHT.

Hexane and other solvents: Used in the extraction process, these industrial chemicals can have toxic effects.

CLA is not only known to help fight cancer and diabetes, it may even help you to lose weight, which cannot be said for its trans-fat substitutes.

Good-old-fashioned butter, when made from grass-fed cows, is rich in a substance called conjugated linoleic acid (CLA). Much of the reason why butter is vilified is because it contains saturated fat. If you're still in the mindset that saturated fat is harmful for your health, then please read the Healthy Fats section of my Optimized Nutrition Plan to learn why saturated fat is actually good for you.

4. Vegetable Oils

Of all the destructive foods available to us, those made with heated vegetable oils are some of the worst. Make no mistake about it--vegetable oils are not the health food that you were lead to believe they were. This is largely due to the fact that they are highly processed, and when consumed in massive amounts, as they are by most Americans, they seriously distort the important omega-6 to omega-3 ratio. Ideally, this ratio is 1:1.

Anytime you cook a food, you run the risk of creating heat-induced damage. The oils you choose to cook with must be stable enough to resist chemical changes when heated to high temperatures, or you run the risk of damaging your health. One of the ways vegetable oils can inflict damage is by converting your good cholesterol into bad cholesterol—by oxidizing it. When you cook with polyunsaturated vegetable oils (such as canola, corn, and soy oils), oxidized cholesterol is introduced into your system.

As the oil is heated and mixed with oxygen, it goes rancid. Rancid oil is oxidized oil and should NOT be consumed—it leads directly to vascular disease. Trans-fats are introduced when these oils are hydrogenated, which increases your risk of chronic diseases like breast cancer and heart disease.

So what's the best oil to cook with?

Of all the available oils, coconut oil is the oil of choice for cooking because it is nearly a completely saturated fat, which means it is much less susceptible to heat damage. And coconut oil is one of the most unique and beneficial fats for your body. For more in-depth information about the many benefits of coconut oil, please see this special report. Olive oil, while certainly a healthful oil, is easily damaged by heat and is best reserved for drizzling cold over salad.

5. Microwave Popcorn

Perfluoroalkyls, which include perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS), are chemicals used to keep grease from leaking through fast food wrappers, are being ingested by people through their food and showing up as contaminants in blood. Microwave popcorn bags are lined with PFOA, and when they are heated the compound leaches onto the popcorn.

These chemicals are part of an expanding group of chemicals commonly referred to as "gender-bending" chemicals, because they can disrupt your endocrine system and affect your sex hormones. The EPA has ruled PFCs as "likely carcinogens," and has stated that PFOA "poses developmental and reproductive risks to humans." Researchers have also linked various PFCs to a range of other health dangers, such as:

Infertility -- A study published in the journal Human Reproduction3 found that both PFOA and PFOS (perfluorooctane sulfonate), dramatically increased the odds of infertility. PFOA was linked to a 60 to 154 percent increase in the chance of infertility.

Thyroid disease -- A 2010 study4 found that PFOA can damage your thyroid function. Individuals with the highest PFOA concentrations were more than twice as likely to report current thyroid disease, compared to those with the lowest PFOA concentrations. Your thyroid contains thyroglobulin protein, which binds to iodine to form hormones, which in turn influence essentially every organ, tissue and cell in your body. Thyroid hormones are also required for growth and development in children. Thyroid disease, if left untreated, can lead to heart disease, infertility, muscle weakness, and osteoporosis.

Cancer -- PFOA has been associated with tumors in at least four different organs in animal tests (liver, pancreas, testicles and mammary glands in rats), and has been associated with increases in prostate cancer in PFOA plant workers.

Immune system problems -- Several studies by scientists in Sweden indicate that PFCs have an adverse effect on your immune system. As described in a report on PFCs by the Environmental Working Group (EWG), PFOA was found to decrease all immune cell subpopulations studied, in the thymus and spleen, and caused immunosupression.

Increased LDL cholesterol levels – A 2010 study in the Archives of Pediatric & Adolescent Medicine5 found that children and teens with higher PFOA levels had higher levels of total cholesterol and LDL or "bad" cholesterol, while PFOS was associated with increased total cholesterol, including both LDL cholesterol and HDL or "good" cholesterol.

I strongly recommend avoiding any product you know containing these toxic compounds, particularly non-stick cookware, but also foods sold in grease-proof food packaging, such as fast food and microwave popcorn. Clearly, if you're eating fast food or junk food, PFCs from the wrapper may be the least of your problems, but I think it's still important to realize that not only are you not getting proper nutrition from the food itself, the wrappers may also add to your toxic burden.

6. Non-Organic Potatoes and Other Fresh Produce Known for High Pesticide Contamination

Your best bet is to buy only organic fruits and vegetables, as synthetic agricultural chemicals are not permissible under the USDA organic rules. That said, not all conventionally grown fruits and vegetables are subjected to the same amount of pesticide load. While Koch focuses on potatoes, as they tend to take up a lot of pesticides and other agricultural chemicals present in the soil, I would recommend reviewing the "Shopper's Guide to Pesticides in Produce"6 by the Environmental Working Group.

Of the 48 different fruit and vegetable categories tested by the EWG for the 2013 guide, the following 15 fruits and vegetables had the highest pesticide load, making them the most important to buy or grow organically:

✓ Apples

✓ Celery

✓ Cherry tomatoes

✓ Cucumbers

✓ Grapes

✓ Hot peppers

✓ Nectarines (imported)

✓ Peaches

✓ Potatoes

✓ Spinach

✓ Strawberries

✓ Sweet bell peppers

✓ Kale

✓ Collard greens

✓ Summer squash

In contrast, the following foods were found to have the lowest residual pesticide load, making them the safest bet among conventionally grown vegetables. Note that a small amount of sweet corn and most Hawaiian papaya, although low in pesticides, are genetically engineered (GE). If you're unsure of whether the sweet corn or papaya is GE, I'd recommend opting for organic varieties:

7. Table Salt

Salt is essential for life—you cannot live without it. However, regular 'table salt' and the salt found in processed foods are NOT identical to the salt your body really needs. In fact, table salt has practically nothing in common with natural salt. One is health damaging, and the other is healing.

Processed salt is 98 percent sodium chloride, and the remaining two percent comprises man-made chemicals, such as moisture absorbents, and a little added iodine. These are dangerous chemicals like ferrocyanide and aluminosilicate. Some European countries, where water fluoridation is not practiced, also add fluoride to table salt

Natural salt is about 84 percent sodium chloride. The remaining 16 percent of natural salt consists of other naturally occurring minerals, including trace minerals like silicon, phosphorous and vanadium

Given that salt is absolutely essential to good health, I recommend switching to a pure, unrefined salt. My favorite is an ancient, all-natural sea salt from the Himalayas. Himalayan salt is completely pure, having spent many thousands of years maturing under extreme tectonic pressure, far away from impurities, so it isn't polluted with the heavy metals and industrial toxins of today. And it's hand-mined, hand-washed, and minimally processed. Himalayan salt is only 85 percent sodium chloride, the remaining 15 percent contains 84 trace minerals from our prehistoric seas. Unrefined natural salt is important to many biological processes, including:

Being a major component of your blood plasma, lymphatic fluid, extracellular fluid, and even amniotic fluid

Carrying nutrients into and out of your cells

Maintain and regulate blood pressure

Increasing the glial cells in your brain, which are responsible for creative thinking and long-term planning

Helping your brain communicate with your muscles, so that you can move on demand via sodium-potassium ion exchange

While natural unprocessed salt has many health benefits, that does not mean you should use it with impunity. Another important factor is the potassium to sodium ratio of your diet. Imbalance in this ratio can not only lead to hypertension (high blood pressure) and other health problems, including heart disease, memory decline, erectile dysfunction and more. The easiest way to avoid this imbalance is by avoiding processed foods, which are notoriously low in potassium while high in sodium. Instead, eat a diet of whole, ideally organically-grown foods to ensure optimal nutrient content. This type of diet will naturally provide much larger amounts of potassium in relation to sodium.

8. Soy Protein Isolate and Other Unfermented Soy Products

Sadly, most of what you have been led to believe by the media about soy is simply untrue. One of the worst problems with soy comes from the fact that 90 to 95 percent of soybeans grown in the US are genetically engineered (GE), and these are used to create soy protein isolate. Genetically engineered soybeans are designed to be "Roundup ready," which means they're engineered to withstand otherwise lethal doses of herbicide.

The active ingredient in Roundup herbicide is called glyphosate, which is responsible for the disruption of the delicate hormonal balance of the female reproductive cycle. What's more, glyphosate is toxic to the placenta, which is responsible for delivering vital nutrients from mother to child, and eliminating waste products. Once the placenta has been damaged or destroyed, the result can be miscarriage. In those children born to mothers who have been exposed to even a small amount of glyphosate, serious birth defects can result.

Glyphosate's mechanism of harm was only recently identified, and demonstrates how this chemical disrupts cellular function and induce many of our modern diseases, including autism. Soy protein isolate can be found in protein bars, meal replacement shakes, bottled fruit drinks, soups and sauces, meat analogs, baked goods, breakfast cereals and some dietary supplements.

Even if you are not a vegetarian and do not use soymilk or tofu, it is important to be a serious label reader. There are so many different names for soy additives, you could be bringing home a genetically modified soy-based product without even realizing it. Soy expert Dr. Kaayla Daniel offers a free Special Report7, "Where the Soys Are," on her Web site. It lists the many "aliases" that soy might be hiding under in ingredient lists -- words like "bouillon," "natural flavor" and "textured plant protein."

The only soy with health benefits is organic soy that has been properly fermented, and these are the only soy products I ever recommend consuming. After a long fermentation process, the phytate and "anti-nutrient" levels of soybeans are reduced, and their beneficial properties become available to your digestive system. To learn more, please see this previous article detailing the dangers of unfermented soy.

9. Artificial Sweeteners

Contrary to popular belief, studies have found that artificial sweeteners such as aspartame can stimulate your appetite, increase carbohydrate cravings, and stimulate fat storage and weight gain. In one of the most recent of such studies8, saccharin and aspartame were found to cause greater weight gain than sugar.

Aspartame is perhaps one of the most problematic. It is primarily made up of aspartic acid and phenylalanine. The phenylalanine has been synthetically modified to carry a methyl group, which provides the majority of the sweetness. That phenylalanine methyl bond, called a methyl ester, is very weak, which allows the methyl group on the phenylalanine to easily break off and form methanol.

You may have heard the claim that aspartame is harmless because methanol is also found in fruits and vegetables. However, in fruits and vegetables, the methanol is firmly bonded to pectin, allowing it to be safely passed through your digestive tract. Not so with the methanol created by aspartame; there it's not bonded to anything that can help eliminate it from your body.

Methanol acts as a Trojan horse; it's carried into susceptible tissues in your body, like your brain and bone marrow, where the alcohol dehydrogenase (ADH) enzyme converts it into formaldehyde, which wreaks havoc with sensitive proteins and DNA. All animals EXCEPT HUMANS have a protective mechanism that allows methanol to be broken down into harmless formic acid. This is why toxicology testing on animals is a flawed model. It doesn't fully apply to people.

Guidelines for Healthy Food

Whatever food you're looking to eat, whether organic or locally grown, from either your local supermarket or a farmer's market, the following are signs of a high-quality, healthy food. Most often, the best place to find these foods is from a sustainable agricultural group in your area. You can also review my free nutrition plan to get started on a healthy eating program today:

It's grown without pesticides and chemical fertilizers (organic foods fit this description, but so do some non-organic foods)

It's not genetically engineered

It contains no added growth hormones, antibiotics, or other drugs

It does not contain artificial anything, nor any preservatives

It is fresh (if you have to choose between wilted organic produce or fresh conventional produce, the latter may still be the better option as freshness is important for optimal nutrient content)

It was not grown in a factory farm

It is grown with the laws of nature in mind (meaning animals are fed their native diets, not a mix of grains and animal byproducts, and have free-range access to the outdoors)

It is grown in a sustainable way (using minimal amounts of water, protecting the soil from burnout, and turning animal wastes into natural fertilizers instead of environmental pollutants)